1. Field of the Invention
The present invention relates to a portable terminal. More particularly, the present invention relates to an antenna apparatus for a portable terminal.
2. Description of the Related Art
In general, a portable terminal is an appliance for providing wireless communication between users or between a user and a service provider via telecommunication base stations, for example. In addition to voice communication services, users may be provided with various other services, such as short message transmission, mobile banking, TV viewing, online games, and VODs (videos-on-demand), via the portable terminals.
Portable terminals are equipped with an antenna apparatus to maintain at least a predetermined level of reception ratio and speech quality regardless of varying radio environments. Antenna apparatuses for portable terminals have different specifications, including length, depending on the frequency band used by corresponding service providers.
The antenna apparatuses may be classified into internal antennas that are installed inside the housing of terminals and external antennas that protrude from the housing. Internal antennas include meander-type antennas, loop antennas, inverted L-type antennas, and planar inverted F-type antennas. External antennas include protruding antennas, which have antenna devices (for example, helical antennas) contained in the housings of the antennas, whip antennas, which are installed on the housings of terminals and adapted to extend/retract, and antenna apparatuses combining features of both helical and whip antennas. To improve the performance of terminals, such as portability, the prevailing trend is to use internal antennas.
Meanwhile, portable terminals are equipped with various additional apparatuses to provide more functions. In particular, camera modules have been rapidly developed recently, and, in accordance with current trends, most portable terminals are equipped with camera modules.
As the camera modules incorporate additional features such as an optical zoom function, their size increases. Consequently, the circuit configuration of the circuit boards of portable terminals, on which the camera modules are mounted, needs to be modified. Such modifications have a direct influence on internal antennas.
In conventional internal antenna apparatuses, the antenna device is directly connected with the RF (radio frequency) circuitry on the circuit board. This is because, as in the case of conventional external antennas, internal antennas are mounted on the upper end of the terminal housing for optimal radiation characteristics. Thus, the RF circuitry's position on the circuit board does not need to be changed to accommodate an internal antenna.
However, when camera modules increase in size, such as by incorporating an optical zoom function, the RF circuitry must be moved. More specifically, a mounting space must be secured in the rear portion of the terminal housing to mount a camera module having an optical zoom function. The camera module must be mounted on the upper end of the rear portion of the terminal housing because a battery pack is generally mounted on the lower end of the rear portion of the terminal housing. As a result, the antenna device, which is mounted on the upper end of the terminal housing, must be separated from the RF circuitry which is installed on the circuit board.
When the RF circuitry and the antenna device are spaced apart from each other in this manner, signal quality may degrade due to noise and loss. In an attempt to solve this problem, efforts have been made to move the radiation unit of internal antennas towards the RF circuitry. However, the position of the radiation unit is difficult to change, because such changes make it difficult to provide the stable antenna characteristics (for example, radiation performance) which are necessary for the terminal and affect the terminal design.
Accordingly, there is a need for an improved antenna apparatus for a mobile terminal having an antenna device which may be separated from the RF circuitry, while still maintaining stable operating characteristics.